1. Field of the Invention
The present invention relates to a unique combined safety lid and mug, and in particular, to a mug and lid combination in which the lid is provided with means for securely retaining the, lid at the mouth of the mug to effectively seal the mouth of the mug and prevent spillage of the liquid contained therein.
2. Description of the Related Art
Many of the currently-available lids suffer from a number drawbacks, the most serious being that these lids are not securely retained at the mouth of the mug, which allows spillage of the liquid if the mug is tipped over. Some of these lids also make it inconvenient for a user to drink from the mug since an insecure lid usually means that the user must hold the lid while drinking.
Several attempts have been made to remedy this drawback. For example, snap-fit lids were provided, but they are unreliable since they must be entirely snapped in place to be effective.
Another example is U.S. Pat. No. 4,582,218 to Ross, which discloses a mug 10 which is specifically provided with a recessed shelf 30 extending inwardly from the internal wall 20 of the mug 10. Gaps 32 are provided in the shelf 30. A lid 40 is provided with tongues 48 and 50, which are adapted to be inserted through the gaps 32. The lid 40 is then rotated about the shelf 30 to secure the lid 40 to the mouth of the mug 10. However, the mug and lid combination of U.S. Pat. No. 4,582,218 suffers from the drawback that it is neither reliable nor convenient to use, since the user must ensure that the tongues 48 and 50 have been inserted all the way through the gaps 32 before rotating the lid 40. If the tongues 48 and 50 are not rotated sufficiently far away from the gaps 32, then the lid 40 is not securely retained. Further, the securing mechanism utilized by U.S. Pat. No. 4,582,218 requires precise interaction between the various elements of the mug 10 and the lid 40. Since the nature of ceramic makes it difficult to manufacture ceramic mugs to meet precise sizes and shapes, the user may therefore find the lid 40 difficult to use with a ceramic mug and possibly unreliable.
As a further example, U.S. Pat. No. 5,018,636 to Ross also discloses a mug 10 with a recessed shelf 30. However, the lid 40 is provided with a pair of retaining means 60 and 70, in the form of a flexible elongated rod 62 or 72 extending from the lower surface 46 of the lid 40 and having a spherical ball 64 or 66 provided at the end of the rod 62. In use, the lid 40 may be inserted into the mug 10 such that the lower surface 46 of the lid 40 rests on the upper portion 31 of the recess 30, with the flexible rods 62 and 72 bent inwardly, and the balls 64 and 66 resting adjacent the lower portion 38 of the recess 30. However, the lid 40 of U.S. Pat. No. 5,018,636 suffers from the drawback that the rods 62 or 72 are very fragile and are easily broken.
Yet another example is U.S. Pat. No. 5,102,000 to Feltman, III, which discloses a mug 11 having an inwardly projecting ring 16 with vertical passages 17 and latch notches 18 formed in the ring 16. The lid 15 has a pair of flexible fingers 30, each having a rounded end 29. In use, the lid 15 is inserted into the mouth of the mug 11 such that the rounded ends 29 pass through the vertical passages 17. The lid 15 is then rotated so that the rounded ends 29 are fitted in the latch notches 18 to provide a secure fit. However, like the lid 40 of U.S. Pat. No. 5,018,636, the lid 15 of U.S. Pat. No. 5,102,000 also suffers from the drawback that the fingers 30 are very fragile and are easily broken.
As yet another example, U.S. Pat. No. 5,217,141 to Ross discloses a lid 205 having a flexible lid sheet 240 sandwiched between a finger pull piece 200 and a lock post part 300. The mug 10 has a ring section 40 comprising a concave inner ring surface 160. The lid 205 may be pushed downwardly through an inner ring/lip interface diameter 80 of the concave inner ring surface 160 and frictionally fitted in the lid cavity diameter 75. The inner truncation diameter 70 is smaller than the lid cavity diameter 75 to support the lid 205 and to prevent the lid 205 from dropping into the chamber 25 of the mug 10. However, the mug and lid combination of U.S. Pat. No. 5,217,141 does not operate reliably and effectively. For example, it is not easy to provide a lid sheet 240 that is sufficiently flexible so that it would be relatively easy to insert the lid 205 into the concave inner ring surface 160 and to remove the lid 205. A lid sheet 240 that is too stiff will be very difficult to use. Likewise, a lid sheet 240 that is too flexible may cause the lid 205 to slip pass the inner truncation diameter 70 and into the chamber 25 of the mug 10 if the lid 205 is pushed too hard. Further, the construction of the lid 205 is complex because three separate components are required.
Thus, there remains a need for a mug and lid combination that is easy to use, can be provided at low cost, and which effectively secures the lid to the mouth of the mug to prevent spillage.